Dropbox: a file hosting service. The free account provides 2 Gb. It offers file synchronisation. Useful when having to share very large files, or to make a backup. For linux, the packages are available at https://www.dropbox.com/install?os=lnx, or can be downloaded through the package manager. (But remember there is also the in house service merci).

Tricider: a tool for brainstorming and votes. Submit one question and get ideas!

Impress: a javascript tool for presentations à la Prezi, but needs editing of hml5/css pages. Install on your machine if you want to be able to make presentations off-line.

Mathjax: a javascript collection to be able to use Latex formulas (including definition of functions) in html pages. Note that $ $ needs to be replaced by \( \) in standard configurations. Install on your machine if you want to be able to make presentations off-line. If you want formulas font to herit styles, use something like <script type="text/javascript" src="MathJax/MathJax.js?config=TeX-AMS-MML_HTMLorMML.js"></script>